This is a Magpul Industries Accessory known as the MIAD/MOE Storage Core, model MAG055-BLK.
Internal core unit for the MIAD(R) as well as the MOE(R)" MOE-K2(R)" and MOE(R) AK Grips* designed to hold two (2) CR123A lithium type batteries in a self contained" water resistant unit. Rubber cap is captured to the unit and can be opened with a push of the thumb.
Features:
Holds two (2) CR123A lithium type batteries
Water resistant
Rubber cap
